Carburetor



CARBURETOR Filed Jan. 51, 1.936

n J s, n m. M W o w 4 m m a 9 4 9 5 0 5 l 5 M Z WJ M g P 3 A r4. I||.. 1..1 M 2/ -L Ta 0 1. P y? M M 4W9 5 0 4 A Y* 0 4 H y ,0 4 i 4 WQ 5 M i R7 N um? 5 Mud Patented Mar. 31, 193@` UNITED STATES PATE-NT OFFICEAppliation January 31, 1936, serial No. 61,797 13 claims. (cl. zel- 50)This invention-relates to carburetors of the v type utilized inconnection with internal combustion engines and particularly to thatclass of internal combustion engines which are employed in theautomotive and aviation industry.

Prior to this' invention, carburetors used for the same purposes forwhich this structure is designed have .given considerable trouble .dueto the multiplicity of minute orices, passages, etc., that are necessaryfor their proper operation. Then, too, the majority of the carburetorsemployed up to this time have been dependent upon a iloat valve forregulating fuel supplied to the carburetor. Additionally Without the useof auxiliary equipment, such as accelerating pumps, it has beenimpossible to obtain smooth and rapid acceleration for the'obviousreason that when an attempt is made to accelerate themotor from a slowspeed to a higher speed, an improper mixture of fuel andcombustion-supporting air is fed to the motor. The problems encounteredin obtaining a rapid vaporization of the fuel have long been recognized,and as a solution to these problems various means, such for example, asthe well known hot spot manifold have been employed but without completesuccess. To employ such means wouldrequire additional bulky castingswhich in addition to the fact that they do not completely effect thedesired results, add considerable weight to the motor which isobjectnable particularly in aviation use.

Therefore, an object of this invention is the provision of an air andfuel mixing device which will be free of the aforementioned decienciesand can be practically and economically constructed.

' Another object of this invention is the provision of a carburetorwhich will serve as a postive fuel and air mixing device for an internalcombustion engine.

Further this invention has for its object the provision of fuel andcombustion supporting air regulating means that will insure a propercombustible mixture under all operating conditions.

This invention further contemplates a carburetor having a minimum ofminute orices, passages, etc., that often, due to the presence ofextraneous matter in the fuel, become clogged.

A still further object of this invention is the provision of a structurehaving the throttle means disposed at the bottom of the device therebysubjecting substantially the entire vacuum produced in the intakemanifold by the pistons to act directly upon the fuel discharge orificeinsuring maximum atomization of the fuel.

Other objects and advantages will appear from the following detaileddescription when considered in connection with the accompanying drawing,in which:

Figure l is a vertical section of my improved carburetor taken partly online I--I of Figure 4;

Figure 2 is a horizontal sectional view taken along thevline 2 2 ofFigure 1;

Figure 3 is a detail plan view of the throttle and choke valves; and

Figure 4 is a sectional fragmentary elevation of the carburetordisclosing in detail the servomotor in section taken on line 4-4 ofFigure 1 that is employed to eiect a setting of the carburetor foridlingwhereby only suiiicient fuel will be fed to the motor to cause itto operate at idling speed, and that will become effective to shut oithe fuel entirely when the motor stops.

Referring to the drawing in detail, particularly Figure 1, I representsthe outer casing of my improved carburetor. This casing may be of steel,aluminum, or the like, and the bottom portion of which may besubstantially cylindrical in form. Made integrally with casing I0 andprojecting from the top thereof is a neck Il, which' has integrallyformed With the top of neck II, a ilange I2 that is adapted to cooperatewith a corresponding ange on a conventional internal combustion engineintake manifold. Flange I2 is provided with a plurality of openings I3so arranged that they will coincide with similar openings in the intakemanifold ange. The entire carburetor assembly is supported in operativeposition by bolts, not shown, which clamp flange I2, with proper gasketmeans disposed therebetween, to the flange of the conventional intakemanifold. Neck lII being substantially cylindrical in shape is adaptedto receive a sleeve I4 which may be secured within the neck by the wellknown process of shrinking or any other suitable method. Sleeve I4 is soformed that when disposed within the neck II, as clearly shown in Figure1, the passageway for intake air and atomized fuel will be of the.

Venturi type. Disposed within the body of casing I0 and secured thereinalso by shrinking, or other known means, is a cor'e member I5 having aplurality of radial vanes I6 formed on the periphery thereof whichcooperate with the core and main body I of the casing to define aplurality of air passages I1. Air passages I1 communicate atthe top ofthe core I5 with a chamber I8 formed by the shoulders I9 of the mainbody of casing Ill and the top of the core I5. Core I5 can be fabricatedof metals such, for example, as aluminum, brass, cast iron or othersuitable alloys, and is provided with a central cylindrical bore adaptedto receive in the top thereof a plug member 20 preferably of brass. Plug20 is also properly secured in position relative to the core I5 by thewell' known method of shrinking, or other suitable means, and isprovided with a cylindrical central bore 2| adapted to receive the valvestem-or metering pin 22, hereinafter referred to as a valve stem. Bore2|, as shown in Figure 1, extends upwardly in plug 20 to a pointsubstantially at the top of the plug and cooperates with,a larger bore23 effected from the top surface' of plug 2B to form la sharp valve seat24. The upper end of valve stem 22 is given preferably a conical shapeand cooperates with the seat 24 to shut off or regulate the amount offuel supplied to the motor. It can readily be seen that the operation ofthe valve head into and out of contact with the sharp valve seat 24 ispositive in action, and there will be less likelihood of extraneousmatter lodging against the seat and holding the valve head out ofcontact therewith.

Due to the conicalshape of the valve head a chamber 25 is formed betweenthe valve head, and the sidewallsjand upper extremity of the bore 2|.Formedvin the plug 20 are passages 25a and 25h which cooperate tointroduce the fuel, from a source of supply not shown, through theconduit 25e to the chamber 25 where on movement of the valve head it isdrawn upwardly and entrained in the air stream passing through theVenturi pasageway and carried to the cylinders for combustion. Themaximum amount of fuel supplied to chamber 25 may be manually regulatedby a valve 25d. The body portion of valve 25d is provided with anexterior thread which cooperatesV with a similar thread in the bore 25e.To prevent valve 25d from moving from its adjusted position as a resultof vibration, pressure is applied to the outer end thereof by a. spring25J and the retaining plug 25g. In order that conduit 25e may be securedto the plug 20 by suitable fittings in communication with the passageway25h, and so that valve 25d may be made accessible for adjustment, aportion of one of the radial Vanes I5 and the casing I0 is cut away,thereby giving free access to the conduit coupling fittings and thevalve 25d. Valve stem 22, preferably fabricated of tool steel, isadapted to slide loosely in bore 2|. As a result, gasoline fed to thechamber 25 will ow freely around the valve stem 22, and, but foradequate sealing means would'iill the space in the bottom of core I5,resulting in a. leakage of fuel. however, is prevented by a diaphragminthe form of a concave disc type spring 26. Spring 26 is secured andsealed to the lower end of valve stem 22 in any conventional manner,such for example, as by a locking screw or jam nuts threaded over theend of the valve stem and secured against the diaphragm on either sidethereof. The spring diaphragm 26 is secured in operative position withadequate gasket means between plug 20 and a sleeve member 21 by bolts28. The upper end of the sleeve 21, as shown in Figure 1, is providedwith a flange of substantially the same diameter as that ofthe plug 20and`has a plurality of openings through which screws 28 pass, whichcorrespond to similar tapped openings in the bottom of plug 20. Sleeve21 formed of gear bronze or similar material, is threaded to cooperatewith the enlarged threaded portion of an operating pin 29. Obviously agreater or lesser displacement ofl the valve stem 22 for a definiteamount of rotation of the operating pin 29'could be effected by varyingthe pitch of the threads on operating pin 29. Pin 29 is adapted to bearagainst and actuate Valve stem 22 against the action of spring 26 whichnormally tends to bias the valve toward the open position. A bell crank30 of conventional design is secured to the bottom end of operating pin29. The outer end of bell crank 30 is adjustably secured to and adaptedto be operated by pin 3| which may be threaded into plate 32 or madeintegrally therewith. Plate 32 further functions as intake airthrottling means and is of similar design to plate 3 3 which serves as achoke. As shown in Figures 2 and 3, these plates are provided withopenings 34 which correspond to and cooperate with the openings I1between the radial vanes I 6.of` core' I5. Both plates 32 and 33 areoperatively secured to the bottom of core I5 by bolts 35 that areprovided with shoulders 36 adapted to bear against the bottom face ofcore I5. These plates are provided with elongated openings 33' throughwhich the bolts 35 are inserted whereby relative movement with respectto core I5 of the plates 32 and 33 in a shutter fashion to limit theintake air is made possible. In order to retain these plates in contactwith each other and the upper face of plate 32 in contact with thebottom face of core I5, springs 31 are utilized between the heads ofbolts 35 and the plate 33. The bottom of the main body' of casing I0 isprovided with an annular flange 38 which forms bearing and guide meansfor both the plates 32 and 33. Made integrally with plate 32 andextending to a point outside the body of the carburetor is an operatinghandle 39 in the-form of an ear' having a passageway 4D therein adaptedto receive operating means, such for example, as an accelerator rod 40'.Then, too, there may be secured in opening 40 or an adjacent opening,one end of spring means not shown which tends to retain the throttlevalve in its closed position. Choke plate or valve 33 is provided with asimilar operating handle 4I having anopening 42 formed therein adaptedto receive operatingmeans 42.

whereby the choke plate' or valve may be operated to close the airpassage to effect a maximum draft on the supplied fuel. Thus far it canreadily be seen that by actuating the throttle plate 32, which functionsas a shutter for the' 46, shown in Figure '4. Due to the reducedpressure in chamber 46 when the motor is functioning `the actuatingelement 41 moves to the right 'to a stop member 48 against the action ofa spring 49 which normally tends to retain the element 41 in the extremeleft hand portion. of chamber '46. Element 4.1 being pivoted at 50 hasan operating lever formed integrally therewith.` Operating lever 5l hasthreaded into the lower end thereof an adjusting screw 52 against whichthe operating handle 39 of the throttle plate is adapted to strike topermit just sufficient fuel and air to be drawn from the carburetor tosupport combustion at idling speeds.

In operation fuel is supplied from a source not shown through conduit25e, passageway 25h through the valve 25d and passageway 25a to thechamber 25. Fuel is then metered out by movement of the throttle plate32, which through the bell crank 30 rotates the operating pin 29, todisengage the valve from its seat 24. The vacuum developed by thereciprocation of the motor pistons draws the fuel in atomized form intothe Venturi passage where it is entrained with the supplied proportionalamount of combustion supporting air. The combustion supporting airisdrawn in throughthe openings 34 in the throttle plate and upwardly-through the passages I1 defined by the radial vanes on the core l5 tothe chamber I8 communicating with the Venturi passage. Fuel willcontinue to be supplied to the Venturi passage as long as throttle plate32 is retained at any of its open positions. InY order to preventvalve22' from completely closing to permit the motor to run at idlingspeeds, means are provided whichdepend upon the operation of the motorfor preventing throttle plate 32 from returning to its closed position.The vacuum developed in tube 44 and chamber 46 of the vacuum motor,draws the operating element 4l over to the stop 48 thereby advancing theadjusting screw 52, which serves als a stop member, to a position thatwill not permit the operating handle to return to the invention beingdesigned and limited only by the terms of the appended claims.

Having thus described my invention, I claim:

1. An air and fuel mixing device for an internal combustion engine,-comprising in combination a mixing chamber, an atomizing means fordischarging fuel into said mixing chamber, means for controlling saidatomizing means air throttling means operatively connected to saidatomizing means, means having radial vanes on the periphery thereofdeflningair passageways for the air, said passageways communicating attheir top with said mixing chamber, and means defining a Venturi passageconnecting the said mixing chamber with the intake manifold of aninternal combustion engine whereby supplied air will entrain atomizedfuel in combustible proportions.

2. An air and-fuel mixing device for an internal combustion enginecomprising in combination a mixing chamber, a choke.valve, an airthrottling valve in contact with said choke valve, stationary. meansadjacent said air throttling and choke valves dening a plurality of airpas'- sageways, a fuel atomizing nozzle discharging into said mixingchamber, means associated with said atomizing nozzle whereby the fuel isatomized at a predetermined rate, means operatively associated with-said control means and said throttle valve whereby a definiteproportion of air and fuel will be supplied to the mixing chamber.

3. An air and fuel mixing device for internal combustion enginescomprising in combination a mixing chamber, a choke valve,'an airthrottling valve in contact with said choke valve, stationary meansadjacent said air throttling and choke valves defining a plurality ofair passageways, a fuel atomizing nozzle discharging into said mixingchamber, means associated with said atomizing nozzle whereby the fuel isatomized at a predetermined rate, adjustable means operativelyassociated with said control. means and said throttle valve whereby adefinite proportion of air and fuel will be supplied to the mixingchamber.

4. An air and fuel mixing devicefor'internal combustion enginescomprising in combination a mixing' chamber, a throttle valve, a fuelatomizing nozzle discharging into said mixing chamber,

valve in one direction whereby sufficient air and `fuel is supplied tothe mixing chamber while the engine is in operation to effect an idlingspeed thereof.

5. An air and fuel mixing device for internal combustion enginescomprising in combination a mixing chamber, a throttle valve, a fuelatomizing nozzle discharging into said mixing chamber, operable meansassociated with said nozzle controlling the rate of discharge of thefuel,` means effective throughout the entire range of the carburetoroperably -associated with said control means and said throttle valvewhereby a definite proportion of fuel and air is supplied to the mixingchamber, means dependent upon the operation of the engine for limitingthe movement of the throttling valve in one direction whereby sufficientair and fuel. is supplied to the mixing chamber while the engine is inoperation to effect an idling speed thereof.

6. A carburetor for internal combustion engines comprising incombination a casing, said casing having a neck portion formed thereon,means disposed within the neck portion of said casing defining a Venturipassage, radial vanes within said casing disposed below and spaced fromsaid Venturi passage defining a plurality Vof air passageways, a fuelsupply nozzle disposed centrally with respect to and below said Venturipassageway whereby supplied air entering the Venturi passage-willentrain fuel'discharged from the supply nozzle.

7. A` carburetor for an internal combustion*- ation .of the engine,passageway defining means connected to the Venturi passage tending toproduce a vacuum in the throttle movement limiting means while the motoris in operation wherebyv into contact with the air throttling valve.

8. A carburetor for an internal combustion engine comprising incombination a casing, said,

casing having a neck portion formed thereon, means defining a Venturipassage disposed within said neck portion, va mixing chamber incommunicationl with said Venturi passage, a fuel nozzle adapted tosupply fuel to said chamber, an air throttling valve forming a closurefor the bottom of said casing, said casing having an annular fiangeformed on the bottom edge thereof forming a guide for said airthrottling valve when rotatively operated, means adapted to limit themovement of said throttle valve in one direction dependent for itsoperation on the operation of the engine, passageway defining meansconnected to the Venturi passage tending to produce a vacuum in thethrottle movement limiting means while the motor is in operation wherebysaid throttle movement limiting means is brought into contact with theair throttling valve.

9. A carburetor for internal combustion engines comprising incombination a casing, said casing having a neck portion formed thereon,means defining a Venturi passage disposed within said neck portion, acylindrical core spaced from and positioned below said Venturi passage,said cylindrical core having radial vanes on the periphery thereofadapted to cooperate with said casing to secure the core to the innerWalls of the casing, said radial vanes defining with the casing airpassages communicating at their top with the Venturi passage, acylindrical plug disposed within and secured to the top of thecylindrical core, said plug having a centrally disposed bore cooperatingwith a larger bore effected from the opposite end of said plug to form avalve seat, a valve positioned within said bore and adapted to slidefreelylwith respect to the plug for controlling the .fuel discharge,interiorly threaded means disposed below and secured to the bottom ofthe plug adapted to receive valve operating means, a spring typediaphragm secured to the bottom-of said plug and valve stem tending tobias said valve to an open position and'forming a. liquid seal wherebyfuel flowing around the valve stem will not be permitted access to thechamber formed in the bottom of the cylindrical core, an air throttlingvalve plate having openings therein adapted to coincide with the abovementioned air passages forming air throttling means, means operativelyconnected to said air throttling means having threads thereon of apredetermined pitch adapted to cooperate with the interiorly threadedmeans to effect an opening or closing of the fuel discharge valvewhereby a definite proportion of air and fuel is fed to theA fjombustionchambers. e10. An air and fuel mixing device for internal combustionengines comprising in combination a mixing chamber, an air throttlingvalve adapted to supply air to said mixing chamber, a fuel dischargevalve adapted to supply fuel to said mixing chamber, means defining aknife edged valve seat for said fuel discharge valve, said valve seatdefining with the head of said discharge valve a fuel chamber, saidmeans further having a passageway communicating with a source of fuelsupply, means whereby the fuel passing through said passageway may berestricted, resilient means for maintaining said passageway restrictingmeans inpredetermined adjustment, means operatively connecting the airthrottling valve to the fuel discharge valve whereby movement of oneeffects an adjustment of the other to supply a predetermined proportionof fuel and air to the mixing chamber. f'

11. A'carburetor for an internal combustion engine comprising incombination a mixing chamber, an air throttling valve adapted to supplyair to said mixing chamber, a fuel discharge valve adapted to supplyfuel to said mixing chamber, means operatively connecting said airthrottling valve and said fuel discharge valve whereby the movement ofone effects a movement of the other to supply to the mixing chamberlproportional amounts of air and fuel, vacuum operated means operativelyassociated lwith said air l throttling valve whereby the air throttlingand fuel discharge valves are maintained in an open position to effect asupply of fuel and air which will be sufficient to operate the internalcombustion engine at idling speed.

12. A carburetor for internal combustion engines comprising incombination a mixing chamber, air throttling means adapted to supply airto said mixing chamber, an operating handle for said means, fueldischarge means operatively connected with said air throttling means andadapted to supply fuel to said mixing chamber, and vacuum operated meansassociated with said handle which while the motor is in operation willlimit the closing of said fuel discharge valve and air throttling means.

13. A carburetor for an internal combustion engine comprising incombination a mixing chamber, air throttling means adapted to supply airto said mixing chamber, fuel discharge means operatively connected withsaid air throttling means and adapted to supply fuel to said mixingchamber, vacuum means operatively associated with said air throttlingmeans whereby the fuel discharge means is maintained sufficiently opento supply the requisite amount of fuel to operate the engineat idlingspeed, positive adjustment means for said air and fuel supply meanswhereby a definite proportional supply of fuel and air will be hadthroughout the entire range of the carburetor.

CONRAD R. ROBIDOUX.

